Starting mechanism for internal-combustion engines



Dec. 14, 1926. 1,610,536

H. H. TRAIL STARTING MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed Jan. 15, 1926 HERBERT HOQAWO TRAN.

mam/w @M By ATTORNEyS Patented Dec. 14;,

stares er Len-n u'r orrica,

srnnrme mnonaursm: FOR INTERNAL-COMBUSTIOLI ENGINES.

application filed January This invention relates to starting mechani'sm for internal Combustion engines of the type embodying a pinion which is automat ically actuated into and out of driving en gagement with a gear on the engine to-be started. 1

One object of this invention is to provide starting motor to-an internal combustion en'- gine gradually and progressively without the aid of any yielding or-cushioning compov nents interposed in the transmission of the driving torque between the -starting motor and the engine. I

Another object of this invention is to provide a simple and sturdy mechani'in'conh prising a cam and pin connection which will automatically cause a pinion to be moved into a substantially solid driving connection with an engine gear and transmit the driving torque of a starting motor to' the engine gear without shock to the mechanism, and cause the pinion to be withdrawn from driving engagement with the gear and gradually returned to its normal position.

A further object of this invention is to provide a mechanism which will automatically cause a pinion to be moved into and out of a substantially solid driving connection with an engine gear, and which will readily fit existing starting motors.

Starting mechanisms oftheautomatic errgaging type use either a spring to yieldingly transmit the driving torque of the starting motor to theiengi'ne gear, or a spring to cushion the axial movement of the engaging member to prevent shock and damage to the mechanism. In'the first mentioned type, should the spring break the starting mechanism becomes inoperative since the driving torque is transmitted through the spring. In a starting mechanism of the second mentioned type the spring is usually interposed between two relatively movable (usually axially movable) components and b ases the engaging member towards its disengaged position causing reciprocation of the engaging member while the engine is being rotated, and should the spring break the mechanism will suffer undue shock or damage.

In accordance with this invention a mechanism is provided which eliminates the disadvantages referred to. The invention broadly consists in providing a cam and pin connection between the driving shaft and 15, ices. Serial No. 81,519.

the pinion, the cam being so shaped as to exert or sufler a force havin two components, one tending to cause axial movement and theother rota tion, and by'suitably arranging the angles of the cam contour the pinion is caused to be moved into driving. engagement with the engine gear and rada mechanism. for" operatively connecting. a'

ually transmit the driving torque o the starting motor to the engine gear, and when the engine starts to runthe pinion is autoinatica ly caused to be withdrawn from engagement with the engine gear and gradually returned to its normal'disengaged position.

Further features ofihe invention will. be described hereinafter and more articularly pointed out inthe appendedc aims,

Referring now to the accompanying drawings, which illustrate by way of example,

convenient forms of the invention Figure 1 is a side elevation showing the parts in their normal position.

Figure 2 is a side view partially in section showing the parts in their operative position, i

Figure 3 is an end" elevation. Figure 4 is a developed view of the cam slot in Figures 1 and a 1 Figure 5 is a sectional elevation showing a modified form of the invention.

Figure 6 is a developed view-of the cam slot in Figure 5. 1

Figure 7 is a side elevation of the en aging element of Figure5 showing the" orm of slot and the preferred form of teeth.

The driving shaft is preferably. the armature shaft 1 of an electric motor, indicated, at 2.. An annular member 3 is mounted on the shaft 1 and rigidly secured thereto as by means of a key 4 and set screw 5. A sleeve Eli 6 is loosely mounted on the shaft 1; and normally disposed within the member 3, At its I inner end the sleeve 6 is enlar ed as at 7 to almost the inner diameter of t e member 3. A pinion 8 is mounted on the sleeve 6 and sphned or keyed thereto as at 9', the pm ion being by a spring 11 which 1s compressed between the pinion and the enlarged part 7 of sleeve 6 in recess 26. The member. 3 is provided with a cam slot 12 thcwall of which coacts with a pin or any suitable prog'cction carried by the enlar ed, portion 7 o the sleeve 6. This in is iIFustrated'asa screw 13 which is locks in position by any suitable means such as a s lit pin 27 placed through a hole in the en urged portion 7 and a corresponding normally held against a nut 10 hole in the pin 13. An anti-friction roller 15 is preferably provided on'the pin 13.

The gear on the engine to be started is indicated at 16. Suitable means such as a spring pressed ball 17 adapted to engage a recess 18 in the member 3, are provided to hold the sleeve 6 in its normal position as shown in Figure 1 and hold the sleeve against accidental movement due to vibration or inclination of the engine.

The operation of the device is as follows When the circuit of the starting motor is closed the shaft 1 is rotated at a high speed in the direction of the arrow, carrying with it the member 3, but the sleeve 6, by reason of the inertia due to its mass, remains temporarily stationary or rotates at a much slower speed than does the shaft. The surface a of the cam slot 12 engages the roller 15 and causes the pinion 8 to be moved into mesh .with the engine gear 16 and this movement continues until the face 6 of the cam slot engages the roller 15 after which a substantially solid drive is obtained. As soon as the engine starts to run under its own power the pinion 8 is over-run by the engine gear 16 and the roller 15 is caused to ride along the face a of the cam slot thereby causing the pinion to be with-drawn from mesh with the engine gear 16.

The speed of the axial movement of the' pinion is not uniform and the cam slot is so designed that the initial engaging movement is relatively slow thereby reducing risk of damage to the teeth. Should the teeth of the pinion abut against the teeth of the engine gear during the initial movement of the sleeve 6 and the axial movement of the pinion be retarded, the cam slot causes the continued axial movement of the. sleeve thus causing compression of the spring 11 and when the sleeve has been moved axially through the pinion, the cam slot, coactin with the roller 15. causes the sleeve 6 an the pinion 8 to rotate, thereby bringing the teeth into registration and allowing the pinion to enter into mesh with the engine gear 16. As soon as the pinion comes into proper registration the spring 11 expands and advances the pinion into contact with the nut 10 while the sleeve 6 is moving the pinion axially into mesh with the gear 16.

It will be noticed that the cam slot is so designed as to exert on the roller 15 a force having two components, one tending to cause axial movement of the pinion and the other tending to cause rotation of the pinion, and as the magnitude of the axial component decreases that of the rotating component increases. This action is accomplished in the example illustrated in Figures 1 and 4 by making the slope of the face a of the camslot ver stee in respect to the axis of the she t 1. rom the face a the cam-slot changes to a point indicated at a When the slope of the cam-slot changes more rapidly until it becomes substantially parallel to the shaft axis at the point, I), after which the face of the cam-slot rises at a steep angle in respect to the axis of the shaft 1 as indicated at D for the purpose of arresting the axial movement of the sleeve 6 withoutshock, as the normal driving position of the roller 15 in respect to the cam-slot is indicated at Z).

The disengaging surface (2 of the cam-slot is preferably of a more uniform line than the surface a so as to cause a steady and quick axial d sengaging movement of the pinion.

As the disengaging movement of the roller 15 is relatively fast, means have to be provided to arrest the roller to avoid undue shock and rebounding. The roller travels along the surface 6 until it reaches the point f when due to its momentum it leaves the surface 6 and comes in contact with the face a at the point G. It will be noticed that the angle of incidence of the roller at G is acute and the roller is caused to travel in a small circle from G to f and then come to rest at its normal position at A where it will be retained by a small spring pressed ball 17.

The lines B in Figures 4 and 6 indicate the path of travel of the centre of the pin 13. The circular movement of the pin at the end of its disengaging movement causes a steady and silent arrest of the pin and the parts connected therewith, and also prevents rebounding and any undue shock to the device.

Figure 5 shows a modified form of the device and is more particularly adapted to be used on engines having comparatively narrow engine gears. The axial movement of the pinion necessary to complete meshing is sum 1 compared with that necessary for engines having wide faced engine gears. Referring to Figure 5, an annular member 3 is securely mounted to the shaft 1 by the means of the key 4 and the lock screw 5. The pinion 24 is loosely mounted on the shaft 1.

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The sleeve 25 is mounted for axial inovcment on an extension 23 of the pinion 24 and is limited in its travel by the pin 13 which fits in the slot 22 of the extension 23. The spring 11 abuts against the pinion at one end and against the sleeve 25 in the recess 26 biasing the sleeve 25 away from the pinion. The sleeve 25 is provided with a screw threaded hole into which is secured the pin 13 upon which the roller 15 is held. Figure 6 is a developed form of the cum-slot contour preferably used with the modified form of the device as illustrated in Figure 5. The cam face contour is similar to that of Figure 4 as far as (l but the face 6 is a somewhat steeper angle to the angle of the axis of shaft 1 than is the face 6 in Figure 4.

At It the angle of the cam slot changes rapidly until it becomes substantially parallel to the shaft axis at y. The pin is caused to travel in an are from 7' to A. where it rests in its normal position where it is retained by the spring pressed ball 17.

Damage and wear of the forward ends of the teeth of the pinion is greatly reduced by forming the forward ends of-theteeth as shown in Figure 7, at. 20 and 21 in which the end face of the teeth is rounded from the top to the bottom as shown at 21 and also from the end to the" side face 0 posite the driving face'as shown at 20. l y this particular shape of the teeth ends there are no acute corners at the points of contact upon the initial meeting of the teeth of the pinion with the gear.

It will be understood that the term pin as used in the appended claims is intended to include any suitable projection or member to co-act with the can What I claim is 1. An engine starting mechanism including a driving shaft, 2'. member rotatable with said shaft, a pinion mounted for axial and rotary movement with respect to said member, a pin and cam connection between said member and pinion, said cam being formed in said member and having a continuous contour shaped to cause axial movement of the pinion in both directions and to limit the axial movements of the pinion, the cam being so shaped that when said member is rotated with respect to the pinion the cam coacts with the the pinion and impart to it a gradually increasing tendency to rotate and finally rotate it positively at a position intel'i'nediate the limits of its axial movement relative to said member.

2. An engine startingmechanism includ ing a driving shaft, a pinion mounted for axial and rotary movement with respect to" said shaft, an annular member secured to said shaft, a cam formed in said member, and a pin adapted to traverse the surface of said cam and impart-movement to the pinion, said cam having a continuous surface so shaped that rotation of theannular memher with respect to said pinion causes axial movement of the'pinion at a gradually increasing velocity and imparts to the pinion a gradually increasing tendency to rotate, positive rotation of the mgplace when it reaches a position ad'acent but spaced fromtbe forward extremity of the cam surface.

3. An engine starting mechanism including a driving shaft, a hollow cylindrical member surrounding said shaft and rigidly secured in concentric relation thereto. a pin ion having an extension slidable into and out of the space between said shaft and member, a sleeve mounted on said extension pin to cause axial movement of.

ejection coacting with witha gear on the engine to be pinion finally tak-v and axially slidable a limited distance thereon, a cam formed in said annular member, a pin carried by said sleeve and adapted to traverse the surface of said cam, and a spring biasing the pinion away from said 7 sleeve, said cam being so shaped that rotation of said member with respect to said pinion imparts to the pinion an axial movement at a gradually increasing tendency to rotate and finally causes positive rotation of the pinion when the latter is in a position adjacent but spaced from the forward extremity of the cam.

4. Engine. starting mechanism including a driving shaft, a hollow cylindrical member surrounding said shaft and secured in concentric relation thereto, a pinion mounted for rotary and axial movement with respect to said shaft, a sleeve rotatable with said pinion but capable of a limited axial move- 55 ment with respect to said pinion, a pin and a cam-slot, said pin andslotbeing provided one on said sleeve and the other on said annular member, the pin being adapted to traverse the surface of the cam-slot, and the slot being shaped to resemble an ellipse with its major axis inclined with respect to the axis of the driving shaft.

5. Engine starting mechanism as claimed in claim 4, wherein the leading'side of said cam-slot is of flatter formation than the trailing side.

6. An engine starting mechanism comprising a driving shaft, a member rigidly 'secured. to and rotatable with said shaft, a mu sleeve freely mounted for axial movement with respect to said shaft, a pinion mounted for axial movement with respect to said shaft, a driving connection between the sleeve. and pinion whereby the sleeve and pinion rotate together, but are capable of relative axial movement with respect to each A 4 other, a projection on said sleeve, said proa cam-slot, in said member to cause axial movement of said pinion into and out of driving engagement started, and means biasing the said pinion to one end of its axial relation to said sleeve.

7. An engine starting mechanism comprising a driving shaft, a member rigidly secured to and rotatable with said shaft, a. sleeve freely mounted for axial movement with respect to said shaft, a pinion mounted for "axial movement with respect to said shaft, a driving connection between the sleeve and pinion whereby the sleeve and pinion rotate together, but are capable of relative axial movement withrespect to each other, means for biasing said pinion towards one end of-its axial relation to the said sleeve. projection on said sleeve which coacts with 'a-"eam-slot in said member to causethe said ninion to be moved into and out of driving. engagement with a gear on the engine tobe started, said cam-slot having a shape resembling that of an ellipse with its major axis disposed at a substantial angle toctha axis of said driving shaft.

8. An en ine starting mechanism comprising a driving shaft, a pinion mounted for rotary and axial movement with respect to said shaft, and a pin and cam connection between the said shaft and pinion, the cam being s0 shaped to cause axial movement of the said pinion into driving engagement with a gear on the engine to be started, the said axial movement being gradually retarded, a substantially solid rotary connection being gradually established between the said shaft and the said pinion and a solid drive being established when the pin is at a point spaced from the forward end of said cam-slot.

9. In an engine starting mechanism comprising a driving shaft, a member rigidly scoured to and rotatable with said shaft, a pinion mounted for axial and rotary movement with respect to said member, a cam and -pin connection between said member and when the pinion is rotated with respect to.

pinion, said cam being formed in said member and being so she. ed as to cause axial movement of the pinion in both directions said member, said cam being also adapted to limit the axial movement of the pinion and so shaped that when said member is rotated with respect to said pinion the cam coacts with the said pin to cause axial movement of the pinion and impart to it a graduallv increasing tendency to rotate it and finally rotate it positively at a position intermediate the limits of its axial movement relative to said member, said pinion being so mounted that it is capable of movement v axially with respect to said pin.

10. An engine starting mechanism as claimed in claim 9, wherein the said pinion has an extended portion in which is shaped an elongated slot running substantially parallel to the axis of the said shaft, and means whereby the said pin is caused to coact with the said cam-slot to cause axial movement of said pin with respect to said pinion.

11. An engine starting mechanism as claimed in claim 9, wherein the said pinion has an extension in which is shaped an elongated slot, a sleevefreely mounted on said extension and a pin connection between the said cam-slot, the said pinion and the said s'eeve, the said pin being secured to the said sleeve.

12. An engine starting mechanism comprising a driving shaft, a pinion mounted for rotary and axial movement with respect to saidshaft, a pin and cam connection between the said shaft and pinion, the cam being so shaped that when the shaft rotates with respect to the pinion the cam coacts with the pin to move the pinion axially at a gradually and progressively increasing, velocity until the pinion is in mesh with a gear on the engine to be started, and the pin has reached a point adjacent but spaced from the forward extremity of the cam, and when the pinion overruns the shaft the pin coacts with the cam to cause axial and rotary movement of the pinion with respect to said shaft to draw the pinion out of driving engage ment with the said engine gear, the said cam being so shaped as to cause gradual retardation of the pinion at the end of its axial disengaging movement.

In testimony whereof I aifix my signature. 

